A semiconductor chip can be produced in the following manner. First, a circuit pattern is formed on a semiconductor wafer and an adhesive sheet is bonded to the semiconductor wafer, and then, the semiconductor wafer undergoes the following steps: cutting the wafer into chips (dicing step); washing and drying the sheet; expanding the sheet (expansion step); peeling the chips off from the sheet (pick-up step); and mounting the chips. It is required that the adhesive sheet such as a dicing tape used in those steps has a sufficient adhesive force to adhere the diced chips from the dicing step to the drying step, while reducing such adhesive force in the pick-up step to such an extent that adhesive deposit does not occur.
There has been known an adhesive sheet formed by applying an adhesive layer which will be cured by polymerization with ultraviolet light and so forth, to a base material having a transmittivity when being passed through by an active light such as UV light and/or an electron beam. With this adhesive sheet, the diced chips are picked up after the adhesive strength is reduced by irradiating the adhesive layer with the UV light and curing the adhesive layer with polymerization.
There has been disclosed an adhesive sheet formed by coating the base material surface with an adhesive layer containing a compound (polyfunctional oligomer) having a photopolymerizable unsaturated double bond in its molecule, which maybe turned into a three-dimensional network by irradiation with, for example, an active light. This has been disclosed in Patent Literatures 1 and 2.